New research shows that Antarctic krill store as much carbon as key coastal habitats like mangroves and seagrasses, highlighting their role in carbon storage. However, global warming and overfishing threaten krill populations, and researchers urge for their protection similar to other blue carbon ecosystems.
New research suggests that small marine crustaceans play a crucial role in carbon storage, comparable to vital coastal habitats, and should receive similar protection. The study highlights that a single species, Antarctic krill, stores amounts of carbon on par with key ‘blue carbon’ ecosystems like mangroves, saltmarshes, and seagrasses.
However, krill are also impacted by global heating and potential overfishing, so should be considered for similar protections as other important habitats, say the researchers.
Krill are eaten by larger animals in the Southern Ocean around Antarctica such as whales, seals, and penguins, but are also fished for food and fishing bait, and for use in aquaculture and dietary supplements.
Lead author Dr. Emma Cavan, from the Department of Life Sciences at Imperial College London, said: “For the past decade we have been piecing together the role krill have in carbon cycling, finally resulting in this amazing finding that krill, and their poo, store similar amounts of carbon as some coastal marine plants. I hope this means we can now work towards conserving krill and their valuable Southern Ocean ecosystem with the same gumption as we are seagrasses and mangroves.”
Published in Nature Communications, the study was led by researchers from Imperial College London in collaboration with colleagues from the University of Exeter, the UK Centre for Ecology & Hydrology, the British Antarctic Survey, the Plymouth Marine Laboratory, and the Technical University of Denmark.
Co-author Dr. Simeon Hill, from the British Antarctic Survey, added: “This study shows how we as people are connected to a small creature in a remote location. We benefit from its actions in removing carbon but we also affect it through our own actions which drive climate change.”
Serious Value
Marine life has an important role in locking carbon away from the atmosphere in ocean systems, and the term ‘blue carbon’ was coined over a decade ago to describe the important role of coastal marine plants in this process.
However, the ocean has other ways to store carbon, away from the coasts, and one of these is through animals like krill. Krill are small (around 6cm) but extremely numerous crustaceans that live in the Antarctic seas.
They eat phytoplankton – microscopic plants that take carbon out of the atmosphere as they perform photosynthesis. When krill poo or molt their exoskeletons, the carbon they have absorbed sinks into the deep sea where it can stay for a very long time.
The new study shows that Antarctic krill lock at least 20 million tons of carbon into the deep ocean annually, which equates to $4-46 billion of storage value, depending on the price of carbon.
Co-author Professor Angus Atkinson, from Plymouth Marine Laboratory, said: “Antarctic krill are well known for being at the center of the unique Southern Ocean ecosystem and supporting an important fishery. But this study paints another picture of krill – on their key role in storing carbon.”
Krill Power
The power of krill for storing carbon comes from their huge populations, forming swarms of up to 30 trillion individuals that produce showers of large, fast-sinking fecal pellets and other waste products.
Co-author Dr. Anna Belcher, based at the UK Centre for Ecology & Hydrology, added: “One of the amazing things about krill is that they form massive swarms, which can be over a kilometer in length. This drives a huge ‘rain’ of krill poo after feeding, making krill globally important for locking carbon away from the atmosphere. So, let’s make sure we look after these amazing crustaceans!”
The study also revealed that the depths that these waste products need to reach to remain stored away for at least 100 years were surprisingly shallow (average depth 381 meters), further enhancing their potential. In combination, these factors make the carbon storage from krill similar to that from coastal blue carbon plant stores.
As Antarctic krill are being impacted by rapid polar climate change and targeted by an expanding fishery, the team says both krill populations and their habitat warrant protection to preserve this valuable carbon sink.
Valuing this ecosystem in terms of carbon storage emphasizes how crucial it is to meet climate goals and work towards including carbon in conservation policies.
Reference: “Antarctic krill sequester similar amounts of carbon to key coastal blue carbon habitats” by E. L. Cavan, N. Mackay, S. L. Hill, A. Atkinson, A. Belcher and A. Visser, 8 September 2024, Nature Communications.
DOI: 10.1038/s41467-024-52135-6
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2 Comments
“Global heating” — These are marketing buzz words, not the carefully chosen descriptors of an objective scientist attempting to communicate precisely with his/her audience. Just because someone has jumped through the virtual hoops to receive a PhD, it doesn’t mean they think like the classical ‘disinterested observer.’
Well we are past global warming, this is what the article is about it doesn’t take a PHD to recognise this it doesn’t take a jab at any science to see the results are not the normal cycle . I don’t know what you mean by a classical disinterested observer is this the typical red-neck YouTube commentator?